Previously, we found that 2α-[2-(tetrazol-2-yl)ethyl]-1α,25-dihydroxyvitamin D3 (AH-1) showed higher osteocalcin promoter transactivation activity in human osteosarcoma (HOS) cells and a greater therapeutic effect on ovariectomized (OVX) rats for enhancing bone mineral density than those of 1α,25(OH)2D3 without hypercalcemic side effects in vivo. Although CYP24A1 catalyzes multi-step oxidations toward the CD-ring side chain of the active vitamin D3 [1α,25(OH)2D3], the CYP24A1-dependent metabolism of AH-1 tended to stop at the first step hydroxylation at the C24-position of AH-1...

BACKGROUND: Premenstrual syndrome (PMS) is among the most unfavorable problems in women in reproductive age; however its pathophysiology is still not fully confirmed. Vitamin D as an immunomodulator could prevent inflammatory state before and during menstruation. OBJECTIVE: The aim was to investigate whether there is any relationship between serum vitamin D levels and PMS. MATERIALS AND METHODS: In total, 82 women participate in this case-control study which was conducted in Shahid Akbar-abadi hospital from November 2013 to March 2015...

The multifaceted involvement of the active vitamin D metabolite 1,25-dihydroxyvitamin D3 (henceforth referred to by the synonyms 1,25(OH)2D3, calcitriol or vitamin D) in blunting the growth of cancer cells is amply recognized. In this review we focused our attention on the cross-talk between 1,25 (OH)2D3 and the tumor microenvironment (TME), signaling out stromal cancer-associated fibroblasts (CAFs), the most abundant TME population, as a target for calcitriol anticancer action. In view of the commonality of the phenotypic signature in myofibroblasts, resident in the cancer stroma and in non-neoplastic fibrotic loci, we examined modes of action of vitamin D in non-neoplastic chronic diseases and in cancer to assess mechanistic similarities and divergences...

Recent evidence suggests that 1α,25-dihydroxyvitamin D3 (calcitriol, VD3), the active form of vitamin D (VD), can inhibit the proliferation of microorganisms. In the present study, we conducted in vitro experiments and utilized in vivo murine models to investigate the antimalarial activity of VD3 and its analog, 22-oxacalcitriol (22-OCT), which was designed to cause less hypercalcemia than VD3. VD3 and 22-OCT treatments effectively resolved a Plasmodium chabaudi (Pc) infection in wild-type mice. Reduced parasitemia was observed during the acute phase of infection in the presence of VD3 and 22-OCT, followed by a delayed peak during the chronic stage of infection...

BACKGROUND: Vitamin D insufficiency is common among multiple sclerosis patients, and hypovitaminosis D has been associated with multiple sclerosis (MS) risk and disease activity. OBJECTIVE: To investigate how recommendations on vitamin D3 supplements affect 25-hydroxyvitamin D (25(OH)D) levels in patients with relapsing-remitting MS (RRMS) and to examine the clinical effects associated with changes in 25(OH)D levels. METHODS: In this prospective cohort study, baseline blood samples were collected from 170 natalizumab-treated RRMS patients during winter 2009-2010 and were repeated the following winter...

Importance: Myopia is becoming increasingly common globally and is associated with potentially sight-threatening complications. Spending time outdoors is protective, but the mechanism underlying this association is poorly understood. Objective: To examine the association of myopia with ultraviolet B radiation (UVB; directly associated with time outdoors and sunlight exposure), serum vitamin D concentrations, and vitamin D pathway genetic variants, adjusting for years in education...

Vitamin D deficiency and insufficiency are associated with an increased risk of cancer, autoimmune disease, inflammation, infection, cardiovascular disease and metabolic disease, as well as bone and mineral disorders. The vitamin D receptor (VDR), a member of the nuclear receptor superfamily, is a receptor for the active form of vitamin D, 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3], and mediates vitamin D regulation of specific target gene expression. The secondary bile acid lithocholic acid, which is produced by intestinal bacteria, is another natural VDR ligand...

The active vitamin D metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) has important regulatory actions in the gut through endocrine and probably also intracrine, autocrine and paracrine mechanisms. By activating the vitamin D receptor (VDR), which is expressed at a high level in the small intestine and colon, 1,25(OH)2D3 regulates numerous genes that control gut physiology and homeostasis. 1,25(OH)2D3 is a major responsible for epithelial barrier function and calcium and phosphate absorption, and the host's defense against pathogens and the inflammatory response by several types of secretory and immune cells...

BACKGROUND: 1,25-dihydroxyvitamin D3 (1,25-OH D3) plays an important role in mineralized tissue metabolism, including teeth. However, few studies have addressed its role in odontoblastic differentiation of human dental pulp-stem cells (hDPSCs). AIM: This study aimed to understand the influence of various concentrations of 1,25-OH D3 on the proliferation capacity and early dentinogenesis responses of hDPSCs. MATERIALS AND METHODS: hDPSCs were obtained from the impacted third molar teeth...

Autoantibodies to the angiotensin II (ANGII) type I receptor (AT1-AA) are associated with preeclampsia (PE). We found that Vitamin D supplementation reduced AT1-AA and blood pressure (MAP) in the RUPP rat model of PE. However, it was undetermined if the decrease in AT1-AA was the mechanism whereby Vitamin D lowered MAP or if it was through factors downstream of AT1-AA. Uterine artery resistance index, placental ET-1 and sFlt-1 are increased with AT1-AA induced hypertension and considered markers of PE in pregnant women...

Chronic kidney disease (CKD) is a highly prevalent condition in the world. Neurological, psychological, and cognitive disorders, related to CKD, could contribute to the morbidity, mortality, and poor quality of life of these patients. The aim of this study was to assess the neurological, psychological, and cognitive imbalance in patients with CKD on conservative and replacement therapy.Seventy-four clinically stable patients affected by CKD on conservative therapy, replacement therapy (hemodialysis (HD), peritoneal dialysis (PD)), or with kidney transplantation (KT) and 25 healthy controls (HC), matched for age and sex were enrolled...

Calcitriol, the active form of vitamin D3, can regulate the gene expression through the binding to the nuclear receptor VDR, but it can also display nongenomic actions, acting through a membrane-associated receptor, which has been discovered as the disulfide isomerase ERp57. The aim of our research is to identify the binding sites for calcitriol in ERp57 and to analyze their interaction. We first studied the interaction through bioinformatics and fluorimetric analyses. Subsequently, we focused on two protein mutants containing the predicted interaction domains with calcitriol: abb'-ERp57, containing the first three domains, and a'-ERp57, the fourth domain only...

BACKGROUND: Autoimmune diseases are pathological conditions characterized by abnormal. responses, accompanied by auto-antibodies to self-molecules. The roles vitamin D in autoimmune diseases has increased significantly in the recent past from its functions in calcium and phosphate homeostasis, it is now involved in the regulations and proliferations of Th1 and Th17 lymphocyte. 1α,25(OH)2D3 in very important in ameliorations of inflammatory disorders arising from autoimmune diseases, but the mechanism by which this is done is still a bone of contentions...

Plasma 25-hydroxyvitamin D (25OHD) half-life (25OHDt 1/2) is a dynamic marker of vitamin D metabolism that can be used to assess vitamin D expenditure and help inform vitamin D requirements. Our group recently established an approach to determine the 25OHDt 1/2 as an alternative biomarker of 25OHD expenditure in humans. The approach uses a small oral dose of stable isotope labeled 25OHD3 [3-(2)H-25OHD(3) (6,19,19-d3)] (d3-25OHD3) (tracer), which is distinguishable from endogenous 25OHD by liquid chromatography tandem-mass spectrometry (LC-MS/MS)...

BACKGROUND: Recent evidence has indicated a potential role of vitamin D3 in a range of neuropsychiatric outcomes, as well as on cognitive function, but conflicting data have left that role uncertain. Understanding potential associations of vitamin D status with psychiatric illness will allow clinicians to better assess therapeutic options. Few studies have examined vitamin D status among a racially diverse group of psychiatric patients who have been hospitalized, and none has done so in the southern US where socioeconomic inequality is high...

Despite differences in the phamacokinetics of 25-hydroxycholecalciferol (25(OH)D3) and 25-hydroxyergocalciferol (25(OH)D2) in man, the effects of these and their 1α-hydroxylated forms (1,25(OH)2D3 and 1,25(OH)2D2) on cellular activity of vitamin D-responsive cells have hardly been compared. We studied differences in the effects of these metabolites on cell number, gene transcription, protein expression and mineralisation of cultured human bone marrow-derived stromal cells (hBMSC) and rapidly mineralising mouse 2T3 osteoblasts...

Vitamin D receptor (VDR) is a member of the nuclear receptor superfamily and regulates the expression of target genes through ligand binding. To express the target gene, coactivator binding to the VDR/ligand complex is essential. Although there are many coactivators in living cells, precise interactions between coactivators and VDR have not been clarified. Here, we synthesized two coactivator peptides, DRIP205-2 and SRC2-3, evaluated their affinity for the ligand-binding domain (LBD) of VDR using 1α,25-dihydroxyvitamin D3, partial agonist 1, and antagonist 2 by surface plasmon resonance (SPR), and assessed their interaction modes with VDR-LBD using X-ray crystallographic analysis...